This comprises a study of flatfish nursery population (with emphasis on commercially important species such as plaice and sole) to examine factors which influence distribution and year class strength of 0-groups in first few months of life. Developments include the assessment of abundance, biomass and production of all mobile epibenthic predators which compete for resources with flatfish juveniles. This research is focused on the centre of a large nursery ground on the North Wales coast, close to Rhyl, Clwyd.